This invention relates generally to devices and systems for supplying a flow of liquid coolant to the working surface of a cutting or grinding tool in the course of a machine tool operation. More particularly, this invention relates to an improved coolant manifold assembly having versatile adjustment capabilities to achieve improved coolant flow to the working surface of the cutting or grinding tool, and thereby achieve improved overall tool operation.
Cutting and grinding wheels are used in a wide variety of industrial machine tool operations in the course of manufacturing many different types of products. In a typical operation, the cutting or grinding wheel is suported from a machine housing and is rotatably driven to perform a desired cutting or grinding operation upon a selected workpiece. In some operations, a plurality of cutting or grinding wheels are ganged together for rotation as a unit to perform a desired cutting or grinding operation relative to one or more workpieces. As one example of such machine tool operations, a gang of relatively narrow cutting wheels are commonly used for precision cutting of ceramic based materials in the production of read/write heads for compute disk drive units or the like. In such cutting operations, the cutting wheels are typically rotated at a relatively high speed on the order of eight to ten thousand rpm.
In industrial cutting tool operations, a liquid coolant is commonly supplied at a controlled flow rate onto the working surface of a rotating cutting or grinding wheel. The liquid coolant typically comprises a water-based solution of selected polymers, wetting agents, and/or other components intended to improve the cutting or grinding operation. More specifically, the coolant is designed to carry thermal energy away from the cutting tool, together with grit or debris which may be present on the working surface as a result of the cutting or grinding operation. These functions advantageously result in a cleaner tool working surface, thereby reducing tool wear and improving the quality of workpiece surface finish.
In the past, devices for supplying coolant flow to a cutting tool working surface have generally comprised relatively simple nozzle arrangements through which a regulated coolant stream is projected toward the cutting or grinding tool. However, such nozzle arrangments have not adequately accounted for air film boundary layers which can occur particularly with cutting or grinding wheels rotated at relatively high speeds. The presence of an air film boundary layer can prevent thorough or intimate coolant contact with the tool working surface, resulting in inadequate dispersal of heat, grit, and debris. Relatively soft pads or flaps have been proposed to ride against the cutting tool working surface in efforts to disrupt the air film boundary layer, but these approaches have not satisfactorily accommodated tool wear and/or wear of the pad or flaps, wherein such wear spaces the pad or flaps from the tool working surface to permit reoccurence of the undesired air film boundary layer.
There exists, therefore, a significant need for an improved coolant manifold arrangement for effectively supplying a coolant flow into direct contact with the working surface of a machine tool, particularly such as a rotatable cutting or grinding wheel or the like. The present invention fulfills this need and provides further related advantages.